Problems in connection with rotor imbalance in machining device such as machine tools are being made more serious by the use of ever increasing speeds of such machining tools, as for example in the case of high speed cutting (HSC). Attempts are frequently made to compensate for undesired imbalance of rotors, which leads to vibrations. One of the known methods produces imbalance compensation with the aid of imbalance correcting rings as disclosed in the patent publication WO 90/11 862.
In the method and apparatus in accordance with this publication WO 90/11 862 two balancing rings are employed in order to correct a lack of balance of a tool holder and tool. The balancing rings are so spread out in their angular position in relation to the tool holder that the imbalance produced by same is equal and opposite to the imbalance of the tool bolder together with the tool. In order to set the spread of the balancing rings scales are provided on the balancing ring, which extend for example from zero to 359.degree. (complete circle) or only from 90 to 180.degree.. The setting of the balancing rings by with the aid of such scales is complicated and leads to misunderstandings during setting the angle of spread. As a rule poorly phrased directions for use and tables are provided, which combine both the spread and also the imbalance to be set on the balancing rings. This means that only persons trained in balancing techniques are able to make use of such directions for use and tables, something also requiring much time. Furthermore such directions for use and tables frequently only relate to certain specific tool holders with tools of the same manufacturer so that this system is inflexible and not sufficiently accurate.